Heater Hoses & Flanges

What are the heater hoses and where are they located? 

Heater hoses help warm up your car when you turn your heat on.  You might be surprised to learn that heater hoses are also an important part of your vehicle’s cooling system.  What does your heater have to do with cooling?  Well, it’s all got to do with where the heat comes from. 

The heater core is basically a small radiator behind your dashboard.  The water pump sends coolant that’s been heated up by the engine to the heater core through the rubber heater hoses.   The heater hoses run from the water pump to the heater core, behind the firewall, and from the heater core back to the radiator.  The heater hoses carry the coolant, and therefore the heat, to the heater core.  Without heater hoses, you’ve got no heat.  When you turn the heat on, it opens a valve that lets the coolant into the heater core.  The heater core gives off heat into the air, just like a radiator.  You may have heard people say that you should run the heat to cool down an engine that’s running hot.  The idea is to use the heater core as a secondary radiator.  Just be careful not to let your passengers overheat instead of your engine.  The blower fan pushes hot air over the heater core through ducts to your vents to keep you toasty warm on a cold winter’s day. 

How do I know if my ­­­­ heater hoses need to be replaced?        

As mentioned above, if the heater hoses aren’t bringing enough hot coolant to the heater core, then you’ll have low or no heat.  A bad heater hose can do a lot more than ruin a winter commute, though. 

Heater hoses, since they are made of rubber, can crack and wear out over time and start to leak coolant.  Lost coolant can cause all sorts of problems—including engine overheating.  Overheating may damage other engine components.  If your engine is running hot, but you can’t get any heat out of your dash, then odds are you have a heater hose leak.  If you are having cooling problems, but can’t seem to attribute them to any other cooling parts, then you might want to check your heater hoses for cracks, holes, or leaks. 

Can I replace the heater hoses myself?  

Replacing the heater hoses is pretty straightforward.  Before you begin, make sure to let everything cool down to avoid burning yourself.  Then, you’ll want to drain your coolant.  Be sure to dispose of the coolant properly, since it can be harmful to children and animals.  Once that’s done, you’ll just have to loosen the hose clamps on the heater hoses and pull the hoses off.  If they will not come off easily, you may need to cut them with a razor blade.  Make sure to have a drain pan ready in case more fluid comes out of the hoses.  You can then put on the new hoses, tighten the hose clamps, and refill your coolant.